
I'm not a pro and I concentrate mainly on wildlife, but I feel the camera and lens although of course very important are not the only things you need to consider...
A good understanding of the use of flash and lighting is essential for this kind of photography.
Photographing wildlife, I use flash very rarely and tend to rely on natural light, but in the world of glamour and fashion, manipulating light is very important.
I'm sure there are plenty of good books about the genre, but it's such a complex subject that I feel you would benifit more from a course or at least a few trips to a camera club where they tend to hold model evenings and such like, just to get you started.

There are plenty of photographers here on Talk Photography who are experienced in the subject of fashion/glamour who will be able to give a better insight.
Good luck.